The present invention relates to the field of locating systems, and more particularly to a monitoring and locating system implementing secure communications between the monitoring device and the monitored unit to lessen the ability of a third party locating the object, e.g., person, automobile, attached to the monitored unit.
There are numerous methods and systems for locating moveable objects such as automobiles, pets and people. One such system for locating moveable objects, such as a person, utilizes a Global Positioning Sensor (GPS) locator device that may be attached to the object, e.g., carried by the person. The GPS locator device may receive and triangulate signals from each of three or more geostationary satellites and determine the geographical coordinates of the device""s current location. The geographical coordinates may be made available to an individual via a web site by the GPS locator device transmitting the GPS coordinates to either a device monitoring the GPS locator device or to a centralized location. However, GPS locator devices may not be able to receive and triangulate signals because the signals may be blocked or scattered by a variety of objects such as dense tree canopies, heavy clouds, metal roofs, layers of rock, concrete or canyon walls. For example, GPS locator devices may not be able to receive and triangulate signals in or around buildings or homes or in the woods with lots of vegetation. Hence, GPS may be of no assistance in locating an object in certain environments as discussed above. Further, in order for the GPS locator device to include both the capabilities of determining the geographical coordinates of the device""s current location and transmitting that information to another device or centralized location, the GPS locator device becomes bulky and costly to implement.
One system that does not utilize GPS to locate objects, such as children, uses a monitoring device configured to monitor the position of a child by detecting the signal strength of a radio frequency carrier from a transmitter attached to the child. If the signal of the radio frequency carrier is too weak, the child is too far away from the adult who has the monitoring device. When this happens, the adult is informed that the child has wandered too far away through the use of an audio tone or through the use of vibrations coming from the device. Once the adult is notified that the child is too far away, the device also has a locating display for indicating the relative direction of the child with respect to the adult. However, since the transmitter worn by the child simply transmits a signal with no unique identification code at a particular frequency, a third party, e.g., potential abductor, may be able to intercept the signal and with a similar monitoring device track the child. Furthermore, since the transmitter worn by the child simply transmits a signal with no unique identification code at a particular frequency, a third party, e.g., potential abductor, may be able to transmit false information to the monitoring device.
Therefore, there is a need in the art for a monitoring and locating system that does not rely upon GPS and provides secure communication making it more difficult for a third party, e.g., potential abductor, potential thief, to be able to locate the object, e.g., child, automobile, as well as transmit false information to the monitoring device and/or monitored unit.
The problems outlined above may at least in part be solved in some embodiments of the present invention by the monitoring device transmitting a seed of an algorithm and a time synchronization to the monitored unit which will be used in conjunction with an algorithm, e.g., frequency hopping table, stored in both the monitoring device and the monitored unit, to communicate at a particular time and frequency between one another. Time synchronization may refer to the time the monitoring device transmits the seed. Each subsequent transmission from the monitored unit to the monitoring device is in a specific time slot, synchronized with the monitoring device and at a frequency that changes pseudo-randomly. A response from the monitoring device resynchronizes the time slot. A seed may refer to a multiple bit number, e.g., 16-bit number, used in conjunction with these time slots to select a particular frequency stored in the algorithm, e.g., frequency hopping table. Hence, the frequency of each communication between the monitoring device and the monitored unit changes according to the algorithm stored in both the monitoring device and the monitored unit thereby making it more difficult for a third party, e.g., potential abductor, potential thief, to be able to locate the object, e.g., child, automobile, as well as transmit false information to the monitoring device and/or monitored unit.
In one embodiment of the present invention, a method for monitoring and locating an object, e.g., person, automobile, may comprise the step of activating a unit to be monitored by a monitoring unit. The method may further comprise receiving a first packet of data form the monitored unit where the first packet of data comprises an identification. The method may further comprise transmitting a seed of an algorithm to the monitored unit if the identification associated with the first packet of data is a valid identification. The method may further comprise measuring a signal strength of a second packet of data if the second packet of data was received at an expected frequency from the monitored unit. The measured signal strength of the second packet of data indicates an approximate distance the monitored unit is located from the monitoring device.
In another embodiment of the present invention, a system may comprise a monitored unit attached to an object. The monitored unit may comprise a memory unit operable for storing a computer program product operable for determining if the monitored unit has been tampered with. The monitored unit may further comprise a processor coupled to the memory unit. The monitored unit may further comprise an emitter coupled to the processor where the emitter is configured to emit infrared signals to the skin of an individual. The monitored unit may further comprise a detector coupled to the processor where the detector is configured to receive reflections of the emitted infrared signals from the skin. The processor, responsive to the computer program, may comprise circuitry operable for determining if an intensity of the reflections of the emitted infrared signals is less than a threshold. The processor may further comprise circuitry operable for transmitting an indication that the monitored unit has been tampered with if the intensity of the reflections of the emitted infrared signals is less than the threshold.
The foregoing has outlined rather broadly the features and technical advantages of one or more embodiments of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.